The present invention relates to an inkjet printer cartridge including at least one print head for printing data on a support.
In the field of printing, printer units such as printers that include at least one monochrome or color printer cartridge are used in a manner that is known to the person skilled in the art for inkjet printing of data onto a support such as a sheet of paper.
On the inkjet printer cartridge there is usually a thin printed circuit including electrical contact areas connected by conductive tracks to a print head provided with nozzles for ejecting ink.
The printer unit includes a carriage forming a cartridge support and on which the printer cartridge is installed, the carriage moving in translation to print data onto a sheet of paper. This is known in the art.
The printer unit also includes a printing management electronic circuit card connected to the carriage by a ribbon cable.
When the printer cartridge is installed on the carriage, the electrical contact areas thereof are in contact with contact areas of the ribbon cable connecting the carriage to the card.
Accordingly, printing commands from the printing management electronic circuit card are transmitted via the ribbon cable and reach the contact areas of the thin printed circuit on the cartridge, where they are routed directly to the print head to control the printing of data.
The thin printed circuit on the cartridge is a passive circuit and guarantees continuity of the electrical signals transmitted to the cartridge.
These printer cartridges which are available off the shelf are entirely standardized consumable products whose service life is generally of the order of a few months.
The data transmitted to the printer cartridge is sometimes deemed to be sensitive, for example because it is confidential or represents sums of money.
The latter situation is encountered, for example, in the field of franking machines, where franking data representative of a monetary value is transmitted from a unit that generates the data to a printer unit for printing the franking data on an envelope.
Accordingly, in this field, as in all other fields in which sensitive data is printed on a support, the problem arises of securing data during transfer of data between the source of sensitive data and the printer cartridge.
To this end, the data can be encrypted in the source, for example, and decrypted in the printer unit before transmitting it to the printer cartridge.
However, the decrypted data can nevertheless still be intercepted by a fraudster.
It would be equally possible to provide a specific printer cartridge that includes a data decrypting circuit and that is rendered inaccessible from the outside, for example by embedding it in resin.
However, this necessitates modification of the printer cartridge and even the printing system itself.
The problem of securing data is therefore even more difficult to solve when the technology of the printer cartridges and the corresponding printer units must not be called into question and when it is preferable to be able to continue to use printer cartridges and printer units available off the shelf.
It would therefore be beneficial to be able to secure sensitive data to be printed without modifying the printing technology.